Submarine Fiber‐Optic Sensing Reveals Monterey Paleocanyon Evolution With Multi‐Scale Ambient Noise Imaging

Abstract Monterey Canyon, one of the most representative submarine canyons worldwide, remains debated for its evolutionary history due to limited observational coverage and imaging resolution in a complex marine setting. Here we present an advanced seismic velocity model with adaptive resolution, extending around 20 km seaward from the head of Monterey Canyon across the continental shelf to a depth of 1.5 km. This model is constructed using a novel multi‐scale ambient noise imaging framework that integrates cross‐scale distributed acoustic sensing observations from submarine fiber‐optic cable with adaptive shear‐wave velocity inversion based on Voronoi tessellation. Our results reveal low velocity zones at multiple spatial scales—from shallow anomalies near 0.1 km to deeper structures approaching 1.5 km—that define nested paleocanyon geometries, including deeply incised sediment pathways overprinted by younger fault‐guided conduits. By incorporating existing geophysical observations and canyon evolution models, we suggest that these paleocanyons record a multi‐phase evolutionary process: initially conditioned by deep‐seated tectonic activity, subsequently reshaped by climate‐modulated surface dynamics, and ultimately preserved by successive episodes of sediment transports and fault activities. This work offers new insights into landscape evolution at active continental margins and enables deeper understanding of Earth's multi‐layered response to climatic and tectonic forcing. It also underscores the transformative potential of repurposing submarine telecommunication cables as dense, long‐term seismic arrays—paving the way for a new era in marine geoscience.